In 40 pubertal boys with a varicocele a comparative followup study was performed to evaluate the efficacy of surgical correction of the varicocele in this age group in regard to improvement of fertility after completion of sexual maturation. The varicocele was corrected surgically in 24 patients and it was left uncorrected in 16. Testicular atrophy was noted in all cases at the initial visit and after followup. Of the 24 corrected patients 16 had atrophy of at least 1 testis before surgical treatment, whereas only 7 demonstrated atrophy after followup. Of the 16 uncorrected patients testicular atrophy was noted in 8 at the initial visit but 12 had atrophy after followup. Semen examination of 23 patients who had completed sexual maturation demonstrated a higher quality of routine seminal parameters, for example sperm density, sperm motility and percentage of morphologically normal spermatozoa, in the corrected group than in the uncorrected group.